Power System Protection

Traditionally, vulnerability is the level of degradation caused by failures or disturbances, and resilience is the ability to recover after a high-impact event. This paper presents a topological procedure based on graph theory to evaluate the vulnerability and resilience of power grids. A cascading failures model is developed by eliminating lines both deliberately and randomly, and four restoration strategies inspired by the network approach are proposed. In the two cases, the degradation and recovery of the electrical infrastructure are quantified through four centrality measures. Here, an index called flow-capacity is proposed to measure the level of network overload during the iterative processes. The developed sequential framework was tested on a graph of 600 nodes and 1196 edges built from the 400 kV high-voltage power system in Spain. The conclusions obtained show that the statistical graph indices measure different topological aspects of the network, so it is essential to combine the results to obtain a broader view of the structural behaviour of the infrastructure.

Cascading outages can cause large blackouts, and a variety of methods are emerging to study this challenging topic. The Task Force on Understanding, Prediction, Mitigation, and Restoration of Cascading Failures, under the IEEE PES Computer Analytical Methods Subcommittee (CAMS), seeks to consolidate and review the progress of the field towards methods and tools of assessing the risk of cascading failure. This paper discusses the challenges of cascading failure and summarizes a variety of state-of-the-art analysis and simulation methods, including analyzing observed data, and simulations relying on various probabilistic, deterministic, approximate, and heuristic approaches. Limitations to the interpretation and application of analytical results are highlighted, and directions and challenges for future developments are discussed.

Auto-reclose relay is an important relay used to reenergize a line after the line was tripped by main protection relay due to fault occurrence. Failure of auto-reclose relay to reenergize the line will make power can't be transmitted through the line and power system will be in stress condition. Knowledge of auto-reclose protection scheme is quite difficult to be understood and only few power system software has auto-reclose model for power system study and the software are costly. This research is about modelling auto-reclose relay and its' scheme using Matlab Simulink. The developed model has been developed with some limitations to simplify the modelling process and the results gained show the capability of Matlab Simulink software to be used to model the scheme for education and research purpose.

This paper describes a methodology for voltage sag characterization using Matlab/Simulink. It includes fault simulations for voltage sag magnitude calculation using Simulink, based on the SimPowerSystems toolbox, and also considering protection-systems modeling for sag duration calculation. Other sag characteristics, such as phase-angle jump and shape, are described and simulated.

this paper is a result of ongoing activity carried out by Understanding, Prediction, Mitigation and Restoration of Cascading Failures Task Force under IEEE Computer Analytical Methods Subcommittee (CAMS). The task force's previous papers [1, 2] are focused on general aspects of cascading outages such as understanding, prediction, prevention and restoration from cascading failures. This is the second of two new papers, which extend this previous work to summarize the state of the art in cascading failure risk analysis methodologies and modeling tools. The first paper reviews the state of the art in methodologies for performing risk assessment of potential cascading outages [3]. This paper describes the state of the art in cascading failure modeling tools, documenting the view of experts representing utilities, universities and consulting companies. The paper is intended to constitute a valid source of information and references about presently available tools that deal with prediction of cascading failure events. This effort involves reviewing published literature and other documentation from vendors, universities and research institutions. The assessment of cascading outages risk evaluation is in continuous evolution. Investigations to gain even better understanding and identification of cascading events are the subject of several research programs underway aimed at solving the complexity of these events that electrical utilities face today. Assessing the risk of cascading failure events in planning and operation for power transmission systems require adequate mathematical tools/software.

Kebutuhan tenaga listrik yang meningkat dari tahun ke tahun sejalan dengan bertambahnya permintaan energi.Untuk itu diperlukan infrastruktur telekomunikasi yang handal untuk dapat mewujudkan kelancaran pengaturan operasi sistem. Dalam penelitian ini akan dibahas tentang keandalan Teleproteksi. Pada penelitian kali ini akan membahas sistem Teleproteksi di gardu induk Durikosambi ke gardu induk Cengkareng. Setelah melakukan pengujian dan analisis dapat disimpulkan bahwa kondisi sistem Teleproteksi yang digunakan adalah handal untuk melindungi sistem yang ada..

Kata kunci: Teleproteksi, Gardu Induk 150 kV

This paper describes an adaptive distance relaying scheme which can eliminate the effect of fault resistance on distance relay zone reach. Distance relay is commonly used as main protection to protect transmission line from any type of fault. For a stand-alone distance relay, fault resistance can make Mho type distance relay to be under reached and thus the fault will be isolated at a longer time. In this scheme, the relay detects the fault location using a two-terminal algorithm. By knowing fault location, fault voltage at the fault point can be calculated by using equivalent sequence network connection as seen from local terminal. Then, fault resistance is calculated by using simple equation considering contribution from remote terminal current. Finally, the compensation of fault resistance is done onto
calculated apparent resistance as seen at relaying point. The
modeling and simulation was carried out using Matlab/Simulink software. Several cases were carried out and the results show the validity of the scheme.